WTPA42 PHFO 251031 CCB TCDCP2 TROPICAL STORM NEKI DISCUSSION NUMBER 27 NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI CP032009 1100 PM HST SAT OCT 24 2009 NEKI/S GENERAL APPEARANCE HAS NOT CHANGED MUCH IN INFRARED SATELLITE IMAGERY OVER THE PAST 24 HOURS. IN FACT LOOKING AT THE IMAGE FROM EXACTLY 24 HOURS AGO...IT APPEARS THE DEEP CONVECTION IS MORE CONCENTRATED THAN IT WAS YESTERDAY EVENING AT THIS TIME. HOWEVER... BASED ON MICROWAVE IMAGERY FROM A FEW HOURS AGO...SIGNS OF THE INITIAL DECOUPLING OF THE LOW-LEVEL CIRCULATION CENTER...OR LLCC... FROM THE CORE OF THE DEEPEST CONVECTION APPEARS TO BE TAKING PLACE. THIS MAY ACTUALLY BE AN INDICATION OF TILTING OF THE SYSTEM WITH HEIGHT TOWARD THE NORTHEAST. THIS IS NOT UNEXPECTED...SINCE THE LATEST UW/CIMSS ESTIMATE OF ENVIRONMENTAL VERTICAL WIND SHEAR IN THE VICINITY OF NEKI IS FROM 262 DEGREES AT 29 KT. THIS SHEAR IS THE RESULT OF A LARGE UPPER TROPOSPHERIC TROUGH LOCATED JUST WEST OF NEKI. IN ADDITION TO THE ADVERSE SHEARING CONDITIONS...NEKI IS ALSO ENCOUNTERING A BUBBLE HIGH AT THE SURFACE DUE NORTH OF ITS PRESENT LOCATION. ALL OF THE FIX AGENCIES...PHFO...JTWC AND SAB...INDICATE THE LLCC HAS STALLED COMPARED WITH THE POSITIONS PROVIDED FOR 0000 UTC. IT IS POSSIBLE THAT NEKI HAS ACTUALLY DONE A SMALL ANTICYCLONIC LOOP DURING THE PAST SEVERAL HOURS. FOR THIS ADVISORY...HAVE MADE NEKI NEARLY STATIONARY. THE CURRENT INTENSITY ESTIMATES FROM THE SAME FIX AGENCIES RANGED FROM 2.5 TO 3.0. THE 0505 UTC QUIKSCAT PASS OVER NEKI INDICATED SOME 50 KT WIND BARBS WITHOUT RAIN FLAGS. DUE TO THE LACK OF SIGNIFICANT CHANGE IN THE SYSTEM AND THE QUIKSCAT DATA...WILL MAINTAIN NEKI AS A 50 KT TROPICAL STORM FOR THIS ADVISORY. THE SMALL HIGH DUE NORTH OF NEKI IS EXPECTED TO CONTINUE PROPAGATING SLOWLY EASTWARD DURING THE NEXT 12 TO 24 HOURS. AS A RESULT...THE LATEST INDIVIDUAL AND CONSENSUS TRACK GUIDANCE CONTINUE TO SHOW THE SYSTEM WILL BEGIN TO MOVE SLOWLY NORTHWARD WITHIN THE NEXT 12 HOURS. THE GUIDANCE THEN MOVES NEKI AT A SLIGHTLY FASTER FORWARD SPEED TOWARD THE NORTH DURING THE NEXT 24 TO 36 HOURS. THEREFORE... HAVE NUDGED THE LATEST FORECAST TRACK CLOSER TO THE GUIDANCE... ESPECIALLY THE TVCN. NEKI IS FORECAST TO CONTINUE MOVING OVER COOLER SEA SURFACE TEMPERATURES AND LOWER OCEAN HEAT CONTENT VALUES DURING THE NEXT COUPLE OF DAYS. THE COOLING TREND OF THE UNDERLYING OCEAN COMBINED WITH STRONG VERTICAL WIND SHEAR CONTINUES TO SUPPORT THE WEAKENING TREND FROM THE PREVIOUS FORECAST. AS IN THE PREVIOUS FORECAST...AN EXTRATROPICAL TRANSITION IS EXPECTED STARTING ON DAY 2...WITH A COMPLETE TRANSITION WITHIN 3 DAYS. NOTE...WOULD STILL NOT BE SURPRISED IF NEKI IS COMPLETELY SHEARED APART BEYOND 48 HOURS WHEN IT ENCOUNTERS THE STRONG WESTERLIES AND IS ABSORBED BY A MID-LATITUDE SYSTEM OVER THE NORTH CENTRAL PACIFIC OCEAN. FORECAST POSITIONS AND MAX WINDS INITIAL 25/0900Z 24.8N 163.9W 50 KT 12HR VT 25/1800Z 25.6N 164.0W 45 KT 24HR VT 26/0600Z 27.2N 164.1W 40 KT 36HR VT 26/1800Z 29.6N 163.8W 40 KT 48HR VT 27/0600Z 33.1N 162.0W 40 KT...BECOMING EXTRATROPICAL 72HR VT 28/0600Z 45.1N 155.0W 30 KT...EXTRATROPICAL $$ FORECASTER HOUSTON